From my understanding damaging power surges don't always come from outside the house like with lightning strikes. Household appliances such as AC units, refrigerators, etc can cause voltage surges inside the house which over time will decrease the life of electronics. This is why it is suggested that audio and HT equipment be on their own circuit.
In my case, it's too late and it would not be practical to re-wire my theater. I will probably have the whole-house protector installed, then, choose a surge protector for use at my component rack.
Current Equipment: Datasat LS10 w/ Atmos and DIRAC, ATI AT6005, Audio Control Savoy G3, Aerial Acoustics LR5's (LCR), SR3's sides, LR3's (rears),(4) RSL C34E’s (Atmos), Submersive HP, Marantz VP15s1, 123" diag 16:9 Stewart Cima Neve screen, Oppo BDP-103, Palliser Flicks Seating AC Power: Eaton whole-house surge protector at main panel, (3) 20 amp circuits, Surgex XR315 at equipment rack, Cyberpower 1400VA/900 watt, true sine wave UPS.